So correct me if I'm wrong but in sensorless control using space vector modulation you measure the current to know the rotor's position and hence you can know how to drive it
As I underetand At low rpm the problem is the current is small and hence you cannot measure it properly.
To solve this issue, lest say you. Have shunts as current sensors. Couldn't you connect 2 differential op amps to each shunt? One would have a high gain to get an accurate current measurement at low speed while the other would have lower gain to measure at high speed
Would this work? And you would do away with hall effect sensors